If not then could he have been sucessfull at heavyweight in a weaker era with said iron whiskers?

Foster had tremendous difficulty putting on weight to tackle the bigger boys,it wasnt that his chin was so bad ,he lacked the bulk and strength to deal with them,plus his power,sensational at 175 was obviously diminished against the heavies,very few LH,s have carried their power up to Heavy against top men.Foater was an ATG at LH,but even with an Ali chin would only have been an average heavyweight ,imo.